1. Field of the Invention
The present invention relates to an optical waveguide module, particularly relates to an optical waveguide module for detecting intensity of an incident light from a light emitting portion.
2. Description of the Related Art
In recent years, an optical communication system for communicating by replacing a conventional electric signal to an optical signal and propagating it has gotten a lot of attentions. An optical communication system is constituted by an optical waveguide module, etc. obtained by combining an optical waveguide and a photoelectric conversion portion, such as a light emitting portion and a light receiving portion. Such an optical communication system is capable of keeping pace with a higher speed and larger capacity because it uses an optical signal and preventing disadvantages of metal wiring of the related art, such as an electromagnetic noise.
Also, since a light can be handled two dimensionally as an optical propagation path in an optical waveguide module as above, it has been used in an image display device, etc.
For example, an image is displayed by emitting a light emitted from a light emitting portion and scanning the emitted light. It is also possible to irradiate lights from a plurality of light emitting portions to a waveguide and mix in the waveguide to emit.
In the optical waveguide module as above, it is preferable to detect intensity of a light emitted from the light emitting portion and control light intensity of the light emitting portion to stabilize intensity of a light emitted through the optical waveguide.
For example, in the case of mixing lights from a plurality of light emitting portions in the optical waveguide as above, it is necessary that light intensity before mixing is detected and light intensity of respective light emitting portions is adjusted to emit a desired color.
As an optical module mounted structure using the above optical waveguide, it is known that by fixing a film optical wiring formed to have a tilted surface at an angle of totally reflecting a light to be guided and an optical device at a predetermined position of a core by using a bump and using a flexible film optical wiring, positional deviation is suppressed (for example, refer to the Japanese Patent Gazette No. 3285539).
Also, as an optical path converting element using the optical waveguide as above, there is known an optical waveguide wherein an incident/emission surface slightly tilting with respect to a surface perpendicular to the light guiding direction is formed to face to the tilted surface, and a V-shaped groove is formed by the incident/emission surface and the tilted surface (for example, refer to the Japanese Unexamined Patent Publication No. 10-300961).
In the optical waveguide module of the related art as above, to detect intensity of a light emitted to the waveguide, a method of taking out a light by branching a part of a core and a method of separately detecting light intensity at an output end of a core have been generally used.
However, there have been disadvantages that intensity of a light to be guided in the core was deteriorated or the circuit configuration of the optical waveguide module became extremely complicated in these methods.
As a result, even if a connecting efficiency of the core and the light emitting portion is improved, it is difficult to effectively use the incident light because a part of the light to be guided in the core is branched to be taken out. Also, due to the complicated circuit configuration, there was a possibility of declining the degree of integrating elements.